The crossword solution for the term TOP OF AN 'I' is DOT, which is a three letter word. A DOT is a small, round mark that is used to indicate a point in space, or to separate parts of a sentence or list. It is also used in mathematics to indicate the decimal point in a number. In computing, a DOT is used to separate parts of a domain name, such as .com or .org. In printing, a DOT is used to create halftone images.